Design and assembly of an apparatus system based on the Villari effect for detecting stress concentration zone on ferromagnetic materials

  • Nguyen Thi Le Hien
  • Doan Thanh Dat
Keywords: Magnetic field apparatus, stress concentration zone, integrity assessment, defect detection, self-magnetic flux leakage


This paper presents the study results on the fabrication of a structural integrity assessment apparatus by determining stress concentration zones in pressure pipeline and equipment. The apparatus uses a triaxial magnetic field sensor to measure magnetic field components in three axes Ox, Oy, and Oz, in the working range of the magnetic field from -300 μT to 300 μT. The investigation of the selfmagnetic leakage field by this apparatus in the API 5L steel specimens under tensile stress shows a high variation of the magnetic field at a steel elongation lower than 1 mm (corresponding to the elastic deformation state of the material). In the case of an artificial defect, the apparatus can detect a change in the magnetic field caused by stress concentration.


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Hình 2. Hình ảnh từ thông của vật liệu từ tính trong từ trường đều (a) khi không xuất hiện khuyết tật và (b) khi xuất hiện khuyết tật
How to Cite
Nguyen Thi Le Hien, & Doan Thanh Dat. (2021). Design and assembly of an apparatus system based on the Villari effect for detecting stress concentration zone on ferromagnetic materials. Petrovietnam Journal, 1, 68 - 75.

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